Standard Definitions:
GSF:  Gross Square Feet,   the actual area of the "built" construction, measured to all of its exterior faces and including ALL floors, whether occupied or mechanical equipment.

DSF: Deductible Square Feet includes all of the Building-wide common facilities such as exit stairs, elevators, common HVAC ducts and plumbing or electrical chases, main lobby, mechanical floors or areas (serving multiple tenants) and other common areas.

USF: Usable Square Feet is the GSF minus the DSF and is the basis for calculating Loss Factors in conjunction with RSF.

RSF: Rentable Square Feet and is determined by the Landlord based on many market factors and the building's efficiency.

LF: is the Loss Factor which is calculated by dividing the difference between RSF and USF by the RSF, (RSF-USF) /RSF).

All of the preceding are typically looked at on a building-wide and  a floor-by-floor basis.

NUSF, which is Net Usable Square Feet, is typically only calculated for multi-Tenanted floors, where common areas such as corridors to common exits and shared bathroom facilities are deducted from the USF to determine each tenant's actual USF and their share of the floor common areas.

New York is famous for the jokes in the Real Estate community about what a square foot of office space really is. An old standby line is that New York landlords calculate their Rentable Areas by measuring the building out to the adjacent street. In reality, it is very easy to prove a building's efficiency and competitiveness through some simple calculations.

For leasing purposes (standards that are used in determining allowable areas for constructing a new building are totally different), New York uses the REBNY (Real Estate Board of New York) standards for measuring commercial office space (as well as retail and residential spaces), unlike Washington and other major cities which have historically used the BOMA (Building Owners & Managers Association) standards.

Prior to 1987 even the REBNY standards were a bit confusing. The '87 standards clarified many issues and gave added benefits to buildings of a certain character. The '87 guidelines allowed owners who utilized "noble" materials such as stone facades to include that area by changing the "glass line" standard (still used by BOMA) to the "face of exterior" standard for measuring gross built areas, removing the handicap of competing with curtain-wall buildings whose glass line was their exterior wall.

Landlords will always try to maximize RSF. If a building's RSF equals the GSF, and the efficiency is in the 80% range (LF of 20%), it should be a very competitive building in doing comparisons between potential office spaces, efficiency and Loss Factors should be looked at carefully to make sure comparison is on an equal basis. If they are, then negotiations can focus on costs and benefits of truly comparable buildings.

Landlords try to, with good and justifiable reason, make the rentable area equal to the Gross Built area. After all, they had to pay the contractors for every square foot of built area and theoretically, without every square foot, whether or not the tenant ever sees or walks on that square foot, the tenant couldn't have his space. If the RF, or Rentability Factor, is 100% and the Building's Loss Factor is still reasonable, 18%-24%, then the tenant is probably getting a fair deal in terms of the space allocation.

It all may seem confusing, and in today's Landlord-oriented market, somewhat a moot point because few tenants, except those over 100,000 RSF where their percentage of the building begins to approach 10%, have any appreciable leverage. CNI's position is that all our clients, large or small, have the same rights to being protected in their Lease conditions and we check all area calculations.

A tenant's RSF equates to a percentage of the entire building and that equates (in building's not "Porter's Wage" basis) to certain "Additional Rents" or contributions such as maintenance and taxes to be made by the tenant periodically. It's important to ascertain the true RSF and the "real" percentage.

It is said that if you have three design professionals measure an office space, you will get four different USF area calculations. Using the REBNY standards correctly, there is only one answer.

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